Protective system.



Patented Nov. 28, 1916.

D. BASCH.

PROTECTIVE SYSTEM.

APPLICATION FILED SEPT. 7. 1912.

UNITED STATES PATENT @FFlCE.

DAVID BASGH, OF SCI-IENECTADY, NEW YORK, ASSIGNCR 310 GENERAL ELECTRIC COMPANLZ, A CORPORATION OF NEW PROTECTIVE SYSTEM.

Application filed September 7, 1912.

i provide a means for opening one or more switches as may be desired for cutting the transmission line or other apparatus either wholly or partly out of circuit, either from the load or the source of energy or both,

- whenever the energy flow through one part of the apparatus to be protected is reversed in direction without a corresponding reversal in direction of flow in another part or other parts, the protecting means, however, not operating to open the switch or switches on the occurrence of a reversal of energy flow in all parts of the apparatus.

Another object of my invention is to supply such and similar protective means with the additional feature that the switches are not opened thereby on the cessation of energy flow in the apparatus, and that if opened by any cause, the switches may be closed and held closed without interference by said protective means when there is no energy in the apparatus.

1 accomplish the first of these objects specifically by connecting to each point of the agparatus at which it is desired to notice "sal of energy, a relay operable to different positions according to the direction of energy flow in the apparatus at those points. Contacts are provided, adapted to be brought into engagement by such relays at each position assumed thereby when influenced by energy flow. Similar sets of contacts are so connected in series, that a circuit is completed through the trip coil or coils of the switch or switches in one direction when the flow of energy at the various points of the apparatus is in the same direction and is completed in a reverse direction through the trip coil or coils when the flow of energy is reversed at all of the various points of the apparatus. lVith such an arrangement no Specification of Letters Patent.

Patented Nov. 28, 1916.

Serial No. 19,061.

energy can flow through the trip coil or coils unless all the relays are held in the same relative positions by reason of energy flow at their respective points of connection to the apparatus being in the desired directions, since the opening of one relay, and even its movement to the opposite position, disrupts the circuit through the trip coil or coils. The breaking of the circuit through the trip coil or coils is followed by the opening o t the switch or switches. This simple protective means, and others possessing its general characteristics, possesses the disadvantage that when there is no energy flow in the apparatus the relays are uninfiuenced and are not bound to maintain any contacts in engagement; hence with a cessation of energy How the engagement of one or more pairs of contacts is likely to be brol-re resulting in the opening or the switche Since these contacts may persist in remaining out of en gagement, it may be dillicult to close the switches without considerable manual manipulation. E propose to overcome this diliiculty by providing a neutral position for one or more of the relays, a position which will be. assumed by means of springs or otherwise when the relays are uninfluenced by a flow of energy in the apparatus. Contacts are also to be brought into engagement when this relay or these relays assume this neutral position. Connections thereto and to the trip coil or coils and the source or" energy for the trip coil or coils, are so arranged that a circuit is completed by the engagement or these contacts. By this means the trip coil or coils are maintained energized after the cessation of flow of energy in the apparatus and there is therefore no tendencv for the switch or switches to open, or, should they be open, no interference with their closmg.

Figure l diagrammatically illustrates the construction of the relay adapted for use in the protective means. Fig. 2 illustrates diagrammatically my protective means applied to protect a three-wire alternating current transmission line. i

The relay I prefer to construct with coils l and 2-, one or" these 1, being fixed, the other coil 2 being pivoted and within the first coil. T he mova le coil controls a contact arm 3. on two sides of which are located the sets or contacts l and 5, the arm being capable of engaging and two coils. for example,

electrically connecting the contacts of either set, but only one set at a time, according to the position assumed by the coil 2 with relation to the coil 1. To hold the contact arm 3 in neutral position, when there is no current flowing through the coils, I prefer to provide the two springs 6, one at each side of the arm 3 as shown. These may be of sufficient strength to pull the arm to and hold it in the neutral position under conditions of no energy flow. An additional contact 7 is provided to be engaged by the contact arm 3 in its neutral position; also the upper contact of each set may be made a part of a single elongated contact as shown in dotted lines where it is desired that they be permanently connected together. This modification of contacts is desirable in carrying out the second object of my invention as will be understood from the further description. This type of relay will herein after be referred to as a pilot wire relay.

To prevent the contact arm 3 from moving upon every reversal of energy flow, I may arrange springs 6 so that the contact arm is maintained normally in the neutral position. in engagement with contact 7 and is only moved into engagement with contacts l or upon a reversal of energy flow accompanied by an overload of a predetermined amount which amount can be deter mined by the tension of springs 6.

In Fig. 2 I have shown my invention as applied to protect any three-phase electrical apparatus wherein it is desired that the direction of flow of energy he the same at both sides of the apparatus. For the apparatus to be protected I have chosen to show a transmission line 8. Connected to each end of each conductor of this line is a. current transformer 9; also to each end of the line is connected a set of potential transformers 10; in this instance the potential transformers are connected in Y. These current and potential transformers supply the pilot wire relays which may he of the construction illustrated in Fig. 1, one of the'coils 1 and 2 of each relay being supplied by one of the current transformers, the other coil being supplied by one of the potential transformers.

The transmission line is provided with oil witches 11 to entirely out the transmission line from service. These oil switches are controlled by the low voltage trip coils or relay windings 12, which are normally energized, being deenergized to allow the oil switches to open in any desired way. In Fig. 2 I have shown the trip coils 12 as holding the switches 11 against the action of springs 12". A pilot wire 13 is used to connect the trip coils or relay windings in series. The source of energy for the trip coils may supply direct or alternating current. For the purposes of this description,

I haveshown the two conductors 14 as supplying the necessary current for the trip coils, though it will be understood that the use of either or both of these additional conductors is not a necessary feature of the invention. One of these conductors 1 f has been marked as the positive conductor and the other as the negative conductor, which, however, is merely for ease in the further description. If the current supplied to the trip coils is direct, these symbols may be re arded as indicating the conventional positive and negative poles, and in case the energy supplied to the trip coils is alternating, these may likewise be the positive and negative poles at some particular instant, although it will be understood that at some other instant the signs should be relatively interchanged.

It will be seen from the drawing that similar sets of contacts of the pilot wire relays at one side of the line 8 are connected in series between one side of the trip coil source of energy 14: and the trip coils, and that the like sets of contacts of the other group of pilot wire relays are connected between the trip coils and the opposite side of the source 1 By similar sets of contacts of the pilot wire relays is meant those sets of contacts electrically connected by the respective contact arms 3 when the flow of energy through both ends of the transmission line 8 is in the same direction; for example, it may be assumed for the purpose of this description that when the flow of energy through the transmission line 8 is from left to right, that the contact arms 3 of the pilot wire relays are all moved to and held to the left, engaging with the contacts 4:, and likewise that when the flow of energy through the transmission line 8 is from right to left that the contact arms 3 engage with and connect together the contacts of the sets 5. Of course, it will beunderstood that it is not necessary in practice that the arms 3 all move in the same physical direction when the direction of current through the line 8 is unidirectional, but that certain of the arms 3 may move in one direction and the rest in the opposite direction, in which case it would be necessary to take this fact into consideration in determining which are simi lar sets of contacts.

Assuming that all the contact arms 3 are held in the same direction with unidirectional energy in all parts of the transmission line 8, assuming unidirectional flow be de- "ed, it will be seen that whichever position may be assumed by the arms, as long as the energy is unidirectional, a circuit is completed from the positive side of the source 14 through the trip coils and the pilot wire 13 to the negative side of the source. Should all of the contact arms assume the opposite position, a circuit will still be comopposite direction.

pleted through the trip coils, but now in the This is due to the fact that the sets -Ll or" one group of contacts are connected in series from the positive side of the source 1i, through the trip coils 12 and the pilot wire 13 to the negative side of the source 1%, while the other sets 5 of'contacts of all the pilot wire relays are connected in series from. the negative side of the source 14 through the trip coils 12 and pilot wire 13 to the positive side of that source, reading in the same direction. When the contact arms 3, therefore, connect similar sets 01 contacts, a circuit through the trip coils is completed, but should one arm break its engagement, the circuit through the coils is interrupted resulting inthe deenergization ot' the trip coils 12, and the consequent opening of both switches by the action of the springs 12. Even though one arm 3, or more, proyiding not all, reverse even to the opposite position, the circuit through the trip coils is interrupted. It will thus be seen that no matter in what direction the energy flow happens to be, as long as it is in the same direction throughout the apparatus at the same time, the trip coils 12 will remain normally energized to hold switches 11 closed. The dash pots l2 operatively related to the tripping mechanism of switches 11, provide a short time element between the deenergization of the trip coils or rela windings 12 and the tripping of the switches, so that upon a reversal of energy flow through the whole apparatus, the pilot wire relays in shifting contacts do not cause the opening of the switches.

From the. drawings and the above description, it will be apparent that so long as energy is fed in, for example, at the left hand end of the line 8, and is received from the right hand end thereof, that the trip coils 12 are maintained energized and the switches 11 closed. Should now the direction of energy be reversed at both ends, for example, ted in at the right hand end and received from the left hand end, the only result would be in the swinging over of all of the contact arms 3 from the first position assumed to the opposite position. The trip coils 12 would be deiinergized for the short instant. during the movement of the arms 3, but the switches 11 are held closed due to the action of dash pots 12 which furnish a time. element and prevent the springs 12 from opening the switches 11 immediately upon the deenergization ot' the trip coils or relay windings 12. Should energy, however, for any reason at all, as for example by grounding or otherwise, be taken from the transmission line described between the connections of the transformers, as for example, at the point 15 by grounding, energy would then be fed toward the point 15 from both ends of the lines on at least one of the conductors; one of the pilot wire relays at least would then reverse the position of its contact arm 3, resulting in the breaking of the circuit through the trip coils and the opening of the switches, which is the action desired.

It will, of course, be understood that the protective means illustrated is but one pos sible construction involving my invention and that various modifications of my invention may be used.

What I claim as new and desire to secure by Letters Patent of the United States. is:

1. In a system of distribution, the combination with an energy carrying circuit and switches for controlling said circuit, of electroresponsive tripping means for said switches comprising normally energized trip coils, and means for tripping said switches when said coils are de'e'nergized, an energizing circuit for said trip coils, relays responsive to the direction of energy flow through said switches, similar contacts closed by said relays to maintain said energizing circuit energized when the energy flow through said switches is in the same direction, and other contacts closed by said relays to maintain said energizing circuit energized when there is no energy flow through said switches, said relays operating only when the energy flow through said switches is in opposite directions to open said energizing circuit and thereby allow said switches to open.

In a system of distribution, the combination with an energy carrying circuit and switches for controlling said circuit, of electroresponsive tripping means for said switches comprising normally energized trip coils, and means for tripping said switches when said coils are deenergized, an energizing circuit for said trip coils, energy responsive relays comprising contact arms movable into either one of two positions dependent upon the direction of energy flow through said switches and biased to a neutral position upon the occurrence of no flow of energy through said switches, two sets of similar contacts adapted to be closed when said contact arms are respectively in either one of said first mentioned positions to close the energizing circuit for said trip coils, and other similar contacts adapted to close the ener izing circuit for said trip coils when said contact arms are in said neutral position whereby said switches remain closed not only while the flow of energy through said switches is in the same direction but also when there is no energy liow through said switches.

In a system of distribution, the combination with an energy carrying circuit and switches for controlling said circuit, of electroresponsive tripping means for said switches comprising normally energized trip coils, and means for tripping said switches when said coils are denergized, an energizing circuit for said trip coils, energy responsive relays responsive to the direction of energy flow through said switches, contacts closed by said relays to complete said energizing circuit when the energy flow through said switches is in one direction, second contacts closed by said relays to complete said energizing circuit when the energy flow through said switches is in the reverse direction, and third contacts between said first and second mentioned contact closed by said relays to complete said energizing circuit when there is no energy flow through said switches.

4. In a system of distribution, the combination with an energy carrying circuit and switches for controlling said circuit, of electroresponsive tripping means for said switches comprising normally energized trip coils, and means for tripping said switches when said coils are de'elnergized, an energizing circuit for said trip coils, control relays for said energizing circuit responsive to direction of energy flow through said switches, similar contacts closed to main tain said circuit energized by the movement of said relays in response to the flow of energy through said switches in one direction, a second set of similar contacts closed to maintain said circuit energized by the movement of said relay in response to the flow of energy through said switches in the reverse direction, and retarding means operatively related to said tripping means for preventing said switches from opening as the unidirectional flow of energy through said switches reverses.

5. The combination with electrical apparatus and switches adapted to out said apparatus either partly or wholly from the source of supply and load, of means for operating said switches including trip coils, relays connected to said apparatus, each relay held in one position with energy flow through its point of connection to said apparatus in one direction and in another position with energy flow in the reverse di? rection, and held in a neutral position when tiere is no energy flow, a set of contacts closed by each ofsaid relays in each of said positions, a source of energy for energizing said trip coils, and connections between said trip coils said source of energy and contacts so arranged that a circuit is completed through the trip coils in one direction when the relays are all influenced by energy flowing through their points of connection to the apparatus in certain relative directions, and is completed in the reverse direction when the flow of energy is reversed in direction through all said points and is completed when the relays are in a neutral position.

6. The combination with electrical apgaratus adapted to receive and deliver electrical energy and switches adapted to out said apparatus either partly or wholly from the source of supply and load, of means for operating said switches including trip coils, a relay connected to each side of said apparatus, contacts held in engagement by each relay with energy flow in said apparatus, other contacts held in engagement by each relay when there is no energy flow, a source of energy for energizing said trip coils, connections between said trip coils said source and said first mentioned contacts so arranged that a circuit therethrough is completed by the engagement of said contacts, and other connections between said-trip coils said source and said other contacts for completing a circuit therethrough by the engagement of said other contacts.

In witness whereof I have hereunto set my hand this 5th day of September, 1912.

DAVID BASCH.

YVitnesses:

BENJAMIN B. HULL, HELEN ORFORD.

Gopies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D, 0. 

